Rotary hook for sewing machines



March 1935- H. J. LE VESCONTE 2,035,96

ROTARY HOOK FOR SEWING MACHINES Filed Nov. 50; 1934 Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE ROTARY HOOK FOR SEWING MACHINES Application November 30, 1934, Serial No. 755,493

6 Claims.

The present invention relates to new and useful improvements in a rotary hook for a lock stitch sewing machine, and more particularly to a rotary hook construction which affords novel lubricating means for the interengaging parts between the rotary hook and the stationary bobbin casing.

An object of the present invention is to provide a rotary hook wherein means are provided on the outer face thereof for directing lubricant to the interengaging parts between the rotating hook and the stationary bobbin casing whereby to eliminate any danger of the thread coming in contact with the lubricant.

A further object of the invention is to provide a rotary hook having means including a plate member secured to the outer or back face of the hook for providing lubricant conducting ports or channels for directing lubricant to the interengaging parts between the hook and. the bobbin casing whereby to permit easy access to the ports or channels for cleaning.

The above and other objects of the invention will in part be obvious and will be hereinafter more fully pointed out.

In the accompanying drawing which shows one embodiment of the invention by way of illustration:

Figure 1 is a side view in section showing the assembled rotary hook, bobbin, bobbin casing, and a portion of the bearing and actuating shaft.

Fig. 2 is a front elevation of the rotary hook with the bobbin and bobbin casing removed.

Fig. 3 is an elevation of the plate which is secured to the back of the rotary hook to provide lubricant conducting channels.

Fig. 4 is a sectional view taken along line 44 of Fig. 1.

Fig. 5 is a sectional view, similar to Fig. 4, showing a modification.

The invention relates to lubricating means for the interengaging parts between the rotary hook and the stationary bobbin casing. The rotary hook is fixed to the end of a rotating shaft and the bobbin casing is mounted within and supported by the rotary hook. The bobbin casing is provided with a circumferential rib which engages a groove or raceway in the hook and thus prevents lateral movement of the bobbin casing relative to the rotary hook. A portion of the bobbincasing engages a fixed part of the machine in order to prevent rotation of the casing within the rotary hook. Extending longitudinally and centrally of the rotating shaft is a port which is open at the end of the shaft and which may be provided with wicking. The shaft terminates short of the inner face of the rotary hook in order to provide a recess at the axis of rotation. A sleeve or bushing, in which the shaft rotates, is provided with an opening which registers with an oil hole from which oil may be admitted to the port in the shaft through a suitable opening therein. Thus the lubricating oil may be fed to the recess in the rotary hook. In the hub of the rotary hook are a series of ports communicating with the recess therein. A plate member is fixed to the outer or back face of the rotary hook and. a series of channels are provided between the plate and the hook which communicate with the ports in the hub thereof. The channels formed by the plate member communicate with openings extending through the rotary hook and these openings communicate, in turn, with grooves in the inner peripheral surface of the rotary hook. These grooves lead to the raceway in which the rib on the bobbin casing moves so that oil is thus conducted from the recess in the hook to the interengaging parts between the rotary hook and the bobbin casing. The plate member may be removed so that the oil channels may be easily cleaned. It will be seen that the thread passing between the inner face of the hook and the bobbin casing will not come in contact with the ports containing the oil channels which are on the rear face of the hook.

Referring more in detail to the accompanying drawing, the invention is shown as applied to a sewing machine having a work support H] which is provided with a depending bearing bracket I I in which is mounted a bushing I la. The actuating shaft I2 is mounted within the bushing and carries the rotary hook I3. The actuating shaft l2 may be driven by suitable intermeshing gears, as shown in the copending application of George Sauer, Serial No. 688,512, filed September 7, 1933, and described in detail in the Norman V. Christensen et al. application. Serial No. 670,186. filed May 9, 1933. The shaft l2 may also be driven in the manner shown and described in the copending George Sauer applications, Serial Nos. 716,415 and 716,416, filed March 19, 1934. The particular manner in which the rotary hook is driven forms no part of the present invention.

The rotary hook I3 is of the usual cup-shaped construction with portions cut away to form spaced radial webs or spokes l4 which are formed as a part of the hub 15 and which join the hub to the rim portion I311. The spokes M are illustrated as being slightly inset with respect to the edge of the hook rim although this is not necessary as they may be flush with the edge of the rim. One side wall of the cup is shaped to provide a hook which is adapted to enter the needle thread loop and carry the same about the bobbin casing [6 which is also cup-shaped and is adapted to receive a bobbin l7 therein. The bobbin I! is held within the bobbin casing by a cover or carrier l8. The bobbin casing is provided with a, circumferential rib l9 which fits within a groove or raceway 20 in the rotary hook. 'The bobbin casing is provided with a projecting portion 2| which engages a fixed part of the sewing ma chine in order to prevent the rotation thereof.

ates in the usual manner and further description thereof is not considered necessary.

The present invention relates particularly to a means for lubricating the interengaging parts between the bobbin casing and the rotary hookr When the hub I5 is placed onthe shaft l2 and secured thereto by one or more set screws 22, there is preferably left a space between the end of the shaft and the inner face of the rotary hook thus forming a recess 23 which is closed at the inner face of the hook by a plate 24, in order to retain the oil in the recess and prevent it from reaching the inner face of the hook. V

The hub 15 is provided with a series of ports 25 which extend radially from the recess 23. An apertured plate member 26 is pressed over the hub l5 and is provided with radial arms 26a which make tight fitting contact with the outer face of the spokes M of the rotary hook. The inner portion 21 of the plate 26 is'inclined outwardly to overlie the ports 25 in the hub IS. The arms 2601. of the plate 26 are provided with raised portions 28 which form with the spokes l4 suitable channels 29 which communicate with the ports 25 in the hub. It is to be understood that grooves may be formed in the hook spokes M if so desired, as shown in Fig. 5. The ends of the arms 26a, fit against the inner face of the rim of the rotary hook and the channels 29 communicate with inclined openings 30 which ex-.

tend through the hook spokes I4 and, in turn, communicate with inclined grooves 3| on the inner surface of the rim of the rotary. hook. These grooves 3| lead to the raceway 20 in which the rib I 9 fits.

The actuating shaft I2 is provided with a central bore 32 which opens into the recess 23 and which may be filled with wicking as at W. The bushing I la is provided with an opening 33 which registers with an oil hole 34 in the bearing bracket of the sewing machine. Thus oil may be admitted through the hole 34 and the opening 33 and it will then pass into the bore 32 through an opening 35 in the shaft. The oil will then flow. into the recess 23 from which it will be thrown by centrifugal force through the ports 25 into the channels 29 and finally through the ports .30 and grooves 35 to the raceway 20 so that, as the hook rotates, the interengaging parts between the hook and the stationary bobbin casing, that is, the raceway 2B and the rib l9, will be efiiciently lubricated without danger of soiling the thread. The plate 26 may be removed so that it may be cleaned and so that the various ports may be cleaned to prevent clogging. I

It is to be clearly understood that minor changes in the details of construction and arrangement of parts may be made without departing from the scope of the invention as set forth in the appended claims.

Having thus described the invention, what I claim is new and desire to secure by Letters Patent, is:

1. In a sewing machine, the combination of a rotary hook, a stationary bobbin casing supported therein, said hook and easing having interengagin parts to prevent relative lateral movement therebetween, and means for directing lubricant from a supply adjacent the axis of said hook to said interengaging parts and including a plate secured to the outer face of said hook and forming therebetween a channel communicating with the supply adjacent the axis of said hook and through which the lubricant flows.

I 2. In a sewing machine, the combination of a rotary hook having a hub, a stationary bobbin casing supported therein, said casing and hook having interengaging parts to prevent relative lateral movement therebetween, said hook having a lubricant-containingrecess in the hub, a plu rality of ports leading from said recess through said hub, and means including a plate secured to the outer face of said hook and forming therebetween channels communicating with the ports in said hub for directing lubricant to said interengaging parts. i

' 3. In a sewing machine, the combination of a rotary hook having a hub, a rim portion and spaced radial webs connecting said hub and rim portion, a stationary bobbin casing supported within said hook, said casing and rim portion having interengaging parts to prevent relative lateral movement between the hook and the casing, said hub having a lubricant-containing recess at the axis thereof, a plurality of ports lead-.

ing from said recess through said hub, and means for directing lubricant from said ports to said interengaging parts and including an apertured plate member fitting over said hub and having radial arms tightly fitting against the outer face of said webs for providing channels therebetween communicating with said ports through which lubricant flows to the interengaging parts.

4. In a sewing machine, the combination of a rotary hook having a hub, a rim portion and spaced radial webs connecting said rim portion and said hub, a stationary bobbin casing supported in said hook, said rim portion and said casing having interengaging parts to prevent relative lateral movement between said hook and said casing, ports passing through said webs adjacent said rim portion, grooves on said rim portion communicating with said ports, and means for directing lubricant from a supply adjacent the axis of said hook to said interengaging parts and including an apertured plate member fitting over said hub and having radial arms fitting against said webs and forming therebetween channels through which lubricant flows from the supply to the ports in said webs.

5. In a sewing machine, the combination of a rotary hook having a hub, a rim portion and spaced radial webs connecting said hub and rim portion, a stationary bobbin casing supported in said hook, said casing and said rim portion having interengaging parts to prevent relative lat-' eral movement between said hook and said casing, a shaft to which said hub is secured in position to leave a recess, means for directing lubricant to said recess, and means for directing lubricant from said recess to said interengaging parts and including a plate member having radial. arms tightly fitting the outside of said Webs and through adjacent said rim portion, grooves on the inner face of said rim portion communicating with said ports and leading to said interengaging parts, a shaft on which said hub is secured in position to leave a recess, means for directing lubricant to said recess, radial ports in said hub in line with said radial webs through which lubricant flows from said recess, and means for forming passageways leading from said ports in said hub to the ports in said webs and including a plate member secured to the outer face of said hook and having radial arms making tight contact with said webs and forming therebetween 10 channels through which lubricant flows.

HAROLD J. LE VESCONTE. 

